<script type="module">
	{
		var s = 'Hello world!';
		
		document.write(`是否找到了参数字符串：${s.includes('Hello', 6)}<br></br>`);
		
		document.write(`字符串是否在源字符串的头部：${s.startsWith('Hello')}<br></br>`);
		
		document.write(`字符串是否在源字符串的尾部：${s.endsWith('!')}<br></br>`);
		
		document.write(`字符串是否在源字符串的正数第n个：${s.startsWith('world', 6)}<br></br>`);
		document.write(`字符串是否在源字符串的倒数第n个：${s.endsWith('Hello', 5)}<br></br>`);
	}
</script>